Pressure fluid operated servomotor



p 1, 1951 F. M. HOGUE 2,567,603

PRESSURE FLUI D OPERATED SERVOMOTOR Original Filed Sept. 28, 1946 3Sheets-Sheet 1 FIGI INVENTOR.

FRANCIS MARION HOGUE ATTY.

Sept. 11, 1951 F. M. HOGUE PRESSURE FLUID OPERATED SERVOMOTOR OriginalFiled Sept. 28, 1946 3 Sheets-Sheet 2 INVENTOR. FRANCIS MARION HOGUE%ZWKMW ATTY.

Se t. 11, 1951 F. M. HOGUE 2,567,603

PRESSURE FLUID OPERATED SERVOMOTOR Original Filed sept. 28, 1946 3Sheets-Sheet 3 IN VEN TOR. FRANCIS MARION HQGUE BY %1273?M ATTY.

Patented Sept. 11, 1951 2,567,603 PREss Rr; FLUID OPERATED: SERVOMOTORFrancis: Marion' Hague, Berrien- Springs, Mi c h.,

assignon to Clark Equipment Company, Buchanan Mich, a; corporation ofMichigan Ori'ginab application September 28, 1946, Serial No. 700;068;now'P'atent N'os2,529,393; dated'November 7, 195.0..- Divided and this:application September: 14, 1:949, Serial No. 115,746

7G1aims; (Cl. RID-38) This, invention isconcerned primarily with theprovision of, anauxiliary transmissionforattachmentto astandardautomotivetype transmission and control means. for suchvauxiliary "transmise sion.

' The presentapplication is a, division. of my copen ding application,Serial #700,068, 'filed sap; te' nber 28, [1946, ,now, Patent No.25291395", granted Novembert 27, 1950,, and is, directed imoreparticularly to the fluid motor mechanism for; controllingthe.auxiliarytransmission.

Broadly; stated, the. present invention. is dil ected' to: a. two-speedauxiliary. transmission which is so designed. thatv it: can be.attached. di-..

ready. to. the rear. end wall of a standard. type tiiansmission withoutrequiring changing of any offthe, parts oft. the. standard.transmission,. and which L provides; any output shaft inline with thenormaloutput shaft of, the standard transmission and; equipped. toreceive. the same companion flange for connection. to a.universalijointland propeller shaft;

one of the. objects offthepres entinvention is to, provide, inconjunction. with the transmission ofa heavy duty typevsuchnas; mightheusedion buses, trucks, and similar vehicles, an auxiliarytransmissionwhich provides two additional speed ratios. andwhichflcan beattached tothe conven tionaix transmission without requiring, any sub;st'anti'al mlodificationor change therein o'rl in thedriveQtrainofttheVehicIe. Another. object of the present. invention isto provide. a construction of this type having novel type. of; controlmeans for selectivelycontrolling the shift by which one or the other of;the speed ratios in the auxiliary transmission. can beselected.

' Another object of the presentinventionis. to provides, compact shiftarrangement whichxcan hecontrolled either pneumatically or. hydrauli oally, and which provides for return ofthe'shift ing mechanism to neutralpositionautomatically when the pressure is released in the sh'iftcontrolmechanism.

A still further'advan'tage secured bythe pres 2 junctionwith theaccompanying drawings, will disclose to those skilled inthe art}, the"particular construction andoperati'o'n o'f 'a preferred form of thepresent invention.

In thedrawings: Figure 1 is asectional view'through the'au'z'ziliarytransmission of the present invention},

Figure 2 is; a detail sectional v'ieWo'f theshift mechanism in neutralposition;

ent invention is to enclosethe shift control mechanism' within thehousing of the-auxiliary trans- ,mission without substantiallyenlarging; such housing and without increasing the axial' 'length of thetransmission; so that the tran'smissn' nis kept relatively'sliortill'lngth top'rovi'ddfora propeller shaft of suificient length.

1 Other objects and advantages'ofthe present construction willappear'more fully fromth'e following. detailed; description which; takenin con- Figure 3' is a corresponding view of the shift mechanism in oneof its shifted positions; and

Figure 4 is a sectional transverse View through th auxiliary.-transmission housing: howing the relative position of the shift controlmechanism withrespect to the shifter fork;

Referring now in detail to. the drawings, there is. provided a standardor conventional type transmission. housing 5 having arii' output shaft6; which, asis usual practice,- projects beyond the end .wall ofth'eistandard transmission landfis p'rhvi'dd with splined; portions 8 onits" projecting end and'with a reduced threaded stud-portion'1.

Secured tothe conventional transmission nous; ing;5 and supportedthereon as a. rigid mimic the. auxiliary transmission housing 9,,-whichisoi generally box formation and; is provided in lower. orbottomvwall-withthe drain plug, l 0. The hiousingfisisiprovidedwith-aforward end Wall- IZj-Whichis secured in any suitable manner: to the endwall of the conventional transmission housing 5, and preferably there isprovided an opening; l3 therein within which'is disposed. a bearingcap14, which cap containstherloch ring [5 for securing thev outer race oftheballbearingassembly l6*that supportsthe output shaft 6 of the-maintransmission:

Mounted on the splined portion 8 0fthis 0utpu't shaft is a gear-memberI'll-which, atoneend, bears against? the thrust: washer! i8;locking'ltheinner race of the bearing assembly H6 in position-J Theopposite end-of thehubportion ofigears l;li='is held in position bythe:nut l9 threadedon the'proje'ct'ring Stlldi'l of the shaft 6'.

Thesgear' H is providedwith external gear teeth 2 0 which are inconstant meshing engage ment with the' teethof 'aagear ZZ splinedi upontheilay or countershaft 23 of 'the auxiliarytrans mission. The shaft '23is jouirialieda t its' foh ward end in taperedbearings-iltsecured in'the endwall I 2- of the housing Ii 9-} an'd at -its opp'osi-te end issupported in tapered bearings 25*sup ported in the rear end wall zt ofthe housin 29;

A second gear21-is non rotatablysecured' upon the $11 aft iii and isheld in sp'aced relation to the asc'vgeoe 3 gear 22 by means of thesleeve or spacer member 28.

The gear 28 on the output shaft 6 is provided with an internal annularshoulder portion 29 which receives the outer race 38 of a roller bearingassembly, including the rolls 32 which are sup orted on the extendedannular surface 33 of an enlarged portion 34 of the auxiliarytransmission output shaft 35. The shaft portion 34 is recessed, as at38, to receive the projecting hub portion of the gear I! and end I ofthe shaft 6', and also is preferably provided with external splines 31for receiving an axially slidable clutch member, generally indicated at38, having axially spaced clutch gear portions 39 and 48. The gear I1 isprovided with internal clutch portions 42 overhanging the portion 34 ofthe shaft and adapted to receive the clutch teeth 39 of clutch member 38when it is shifted to the left from the position shown in Figure 1.

Rotatably mounted upon the shaft 35, as by means of the needle rollers43, is a gear member 44, having external gear teeth in constant meshingengagement with the gear teeth of gear 21 on countershaft 23. Gear 44 isalso provided with internal clutch teeth 45 which are adapted to beengaged by the clutch teeth 48 of clutch member 38 when it is shifted tothe right from the position shown in Figure 1. Each of the gears IT and44 is also provided with a tapered synchronizing 3 surface 49 and 41,respectively, adapted to receive corresponding tapered frictionalelements 48 and 49 of a synchronizer sleeve indicated generally at 58.

, The clutch member 38 is provided at circumferentially spaced pointswith radially extending flange portions 52 which project throughsuitable openings 53 in the sleeve 58, and which carry an annular yokering 54 composed of three washers or discs, the intermediate one beingrecessed at spaced points to provide recesses for wire spring members55. The rings 54 are secured to the extending portions 52 of the clutchmember 38 by means of rivets 56 and this entire construction, ingeneral, is similar to that disclosed in United States Letters PatentNo. 2,256,308, issued September 16, 1941 to Leo A. Bixby and RobertLapsley which, in general, provides a blocking type synchronizer forselectively clutching either the ear I! or the gear 44 to the shaft 35.

The shaft 35 as a reduced portion 57 projecting axially out of the rearend wall 26 of the auxiliary transmission housing and journaled in theball bearing assembly 58 secured in position by the bearing cap 59,which bearing cap, in turn, carries a lubricant seal member 68, seatingabout the hub portion of the companion flange 62 secured in splinedengagement on the projecting portion 51 of shaft 35 and held in positionby the nut 83.

It will thus be seen that when the shift mechanism is actuated to movethe clutch member 38 to the left, as viewed in Figure l, the shaft 8 isdirectly coupled to the shaft 35 through the engagement of clutch teeth39 and 42 from the gear 11. When the mechanism, however, is shifted tothe right, as viewed in Figure 1, the gear I! drives the gear 22 which,in turn, drives gear 44 through gear 21, and gear 44 is, in turn,clutched to the shaft 35 through engagement of clutch teeth 48 and 45.

In order to control and select the position and movement of the clutchmember 38, I have disclosed in Figures 2, 3, and 4, a clutch shiftingmechanism, including a shifter fork, indicated generally at 78, havingspaced arm portions 12 which, in turn, are provided with recesses 13adapted to engage the opposite radial faces of the disc assembly 54.Preferably, the clutch fork is provided with strengthening ribs 74 forpreventing deflection thereof, and is also provided with a hub portion15 which may be secured to or slidably mounted on the shift rail 18. Theshift rail 16 is supported at its opposite ends in suitable socketportions 11 formed in flange portion 18 onto which are threaded therings 19.

The sockets I1, flange portions 18 and rings 19, form part of slidingpiston members 89, within the cylinders 83 formed integrally with thehousing 9 in an offset portion 84 thereof. The ends of these cylindersare preferably closed by threaded cap. members 85 which are providedcentrally with tapped pipe openings 86 for receiving conduits or pipesconducting fluid under pressure to the ends of these cylinders.

The pistons 88 are preferably hollow, and are provided with internalannular surfaces 88 within which are slidably mounted cup members 89,these cup members being prevented from movement in one direction withinthe pistons by means of the shoulders 98 formed integral with thepistons and being held against outer move-- ment in the oppositedirection by means of snap rings 92 carried adjacent the open ends ofthe pistons. shoulders 98 and the rings 92, the cup members 89 haveaxial sliding movement and are normally held in neutral position againstthe rings 92 by relatively heavy coil springs 93 disposed about thesocket portions 11 of the pistons and biased at one end against the baseof the cup members 89 and at the opposite end against the flangeportions 18 of the socket portions 11 which are integral with thepistons 88. The hub portion 15 of the shift fork 18 is provided withextended ear portions 94, as indicated in Figure 4, which bear againstthe flanged ends of the cap members 89. When fluid under pressure isintroduced into either end of the shift control assembly, as for examplethrough the, port in the right hand end of the cap member 85, this fluidacts against the piston 88 to move it to the left, as viewed in Figure3. This provides for initial compression of the spring member 93 in theright hand cylinder 88, and when this spring member is compressed to apoint where it exerts suflicient force on the shifter fork 78, the forkis moved to the left, thereby moving the clutch member 38 of Figure 1,together with the synchronizer sleeve 58, to the left.

The blocking action of the synchronizer sleeve will first bring theshaft 35 and the gear I! into synchronism, at which time the pressurebuilt up within the cylinder 83 at the right hand side of the structureshown in Figure 3, will force the clutch member 38 into position toengage clutch teeth 39, with corresponding compression of the left handspring 93 within the left hand cylinder 88. When the pressure isreleased in the right hand cylinder 83, the spring action of the twosprings 93 will force piston 88 back to the outer end of cylinder 83 andwill return the shifter fork 18 back to its neutral position, therebydisengaging clutch teeth 39 and 42 to thereby return the auxiliarytransmission to a neutral position.

A similar operation occurs when pressure is introduced into the lefthand cap member 85 into the left hand cylinder 53 which moves the pistonand its associated cup member 89 to the Within the axial space betweenthe 6 right, first moving the shifter fork into position to ro uceblocking action in the synchronizer 59 and then building up sufficientpressure so that when synchronization is ob tained, the shifter forkW111 more on to engage clutch teeth 40 with clutch teeth 45 of gear 44.Similarly, upon release'of pressure in the left hand cylinder 83, thesprings 93 will cooperate to return the shifter fork 10 to a neutralposition.

Thus it Will be apparent that with the shift control mechanism of thepresent invention, the synchronizer mechanism is adapted to operate forselectively providing ithi" direct dlfiv (Jr a reduced speed drivetnr'ough the auxiliary transmission, and upon eiease or the shiftingpressure, will return the auxiliary transmission to a cente ring orneutral position wit out the use or detllt's or other mechanisms. Also,it is to be observed that with this construction the entire shiftingmechanism is self ntalned within the auxiliary transmission housing, andtheonly connections thereto are the fluid pressure con nections to theend caps 85 of cylinders 80.

The auxiliary transmissionhousing 9 of Figure 4, as disclosed, isprovided with an opening 96 in one side wall thereof, whereby the gearscan be assembled into the housing 9 for mounting upon the various shaftstherein. The opening 96 is adapted to be closed by any suitable coverplate.

It is therefore believed that I have provided a simple, compactauxiliary, transmission and control which may be readily assembled to aConventional type transmission, and which embodies a self-containedactuating mechanism for the synchronizer by which the auxiliarytransmission is clutched to, the main output shaft of the conventionaltransmission.

I am aware that various changes may be made in certain details of thepresent construction, and I therefore do not intend to be limited exceptas defined by the scope and spirit of the appended claims.

I claim:

-1. Control means for shifting a clutch member from a neutral positionto one of two selected operating positions comprising, a shifter forkfor the clutch member, a shift rail upon which said fork is mountedintermediate the ends thereof, piston means having axial bosses slidablyreceiving the ends of said rail, spring means carried by each pistonmeans and engaging opposite end faces of said fork for normallypositioning said fork in a neutral position, axially aligned cylindershaving closed ends and open facing ends for receiving said piston means,said piston means normally lying adjacent the closed ends of saidcylinders, and means for admitting fluid under pressure to one of saidcylinders to move one of said piston means toward the other, therebycollapsing said spring means for each piston means and shifting saidfork out of neutral position.

2.- In combination, a housing having axially alined cylinders, a pistonin each of said cylinders having axial apertured bosses, a shift railsupported in said bosses and having relative sliding movement therein, ashifter fork on said rail intermediate said pistons, means havingsliding movement in said pistons and engaging opposite end faces of saidfork, spring means about said bosses urging said sliding means intoposition to hold said fork normally in neutral position, and means foradmitting fluid under pressure to one of said cylinders for moving theassociated piston axially whereby said spring means are collapsed andrail and fork are shifted axially away from neutral position.

3. A control mechanism for shifting a clutch member from a neutralposition to one of two selected operating positions comprising, ashifter fork, a pair of axially spaced pistons, a shift rail supportedat its ends in said pistons and having limited movement relativethereto, said shifter fork being mounted on said rail intermediate saidpistons, fixed cylinders for said pistons havin closed ends and openfacing ends, said pistons normally lying adjacent the closed ends ofsaid cylinders, spring means in each piston engaging opposite end facesof said fork for positioning said fork into a neutral positionintermediate said cylinders, and means for admitting fluid underpressure into the end of either cylinder to move the piston thereintoward the other of said pistons against the spring means in each pistonand thereby move said fork out of neutral position.

4. In a control mechanism of the character described, the combination ofa pair of axially spaced cylinders, a pair of hollow cup-shaped pistonsone for each of said cylinders and arranged in said cylinders with theiropen ends extending toward each other, cap members one in each of saidpistons mounted for sliding movement axially in the latter, a shift railprojecting axially through said cap members and slidably supported atits opposite ends in said pistons, a shift fork mounted on said shiftrail between said cap members, and spring means one for each of saidpistons between the closed ends of the latter and the cap members at theopen ends thereof for biasing said pistons toward the outer ends of saidcylinders and said cap members outwardly of the open ends of saidcylinders and into engagement with the opposite end faces of said shiftfork.

5. In a control mechanism of the character described, the combination ofa pair of axially spaced cylinders having end walls at the outer endsthereof, a pair of hollow cup-shaped pistons one for each of saidcylinders and arranged in said cylinders with their open ends extendingtoward each other and with their closed ends extending toward the endwalls of said cylinders, cup members one for each of said pistonsextending inwardly of the open ends thereof and mounted therein foraxial sliding movement, a shift rail projecting axially through said capmembers and slidably supported at its opposite ends inwardly of saidpistons, a shift fork mounted on said shift rail between said capmembers, and spring means one for each of said pistons between theclosed ends of the latter and said cap members for biasing said pistonsto a position in which the closed ends of said pistons are disposedagainst said end walls of said cy1-. inders, and for biasing said capmembers outwardly' of the open ends of said pistons into engagement withopposite end faces of Said shift fork to position the latter in aneutral position intermediate said cylinders.

6. In a control mechanism of the character described, the combination ofa pair of axially spaced cylinders having end walls at the outer endsthereof, a pair of hollow cup-shaped pistons one for each of saidcylinder and arranged in said cylinders with their open ends extendingtoward each other and with their closed ends extending toward the endwalls of said cylinders, cup members one for each of said pistonsextending inwardly of the open ends thereof and mounted therein foraxial sliding movement, a shift rail projecting axially through said capmembers and slidably supported at its opposite ends inwardly of saidpistons, a shift fork mounted on said shift rail between said capmembers, spring means one for each of said pistons between the closedends of the latter and said cap members for biasing said pistons to aposition in which the closed ends of said pistons are disposed againstsaid end walls of said cylinders, and for biasing said, cap memberoutwardly of the open ends of said pistons into engagement with oppositeend faces of said shift fork to position the latter in a neutralposition intermediate said cylinders, and openings in said end walls ofsaid cylinders for admitting fluid under pressure into the outer ends ofeither cylinder to move the piston therein toward the other of saidpistons against the force of said spring means in each piston andthereby move said shift fork and said shift rail out of neutralposition.

'7. In a control mechanism of a character described, the combination ofa pair of axially spaced cylinder having end walls at the outer endsthereof, a pair of hollow cup-shaped pistons one for each of saidcylinders and arranged in said cylinders with their open ends extendingtoward each other and with their closed ends extending toward the endwalls of said cylinders, said pistonseach having an axially aperturedcentral boss projecting toward the open end thereof, cup members one foreach of said pistons extending inwardly of the open ends thereof andmounted therein for axial sliding movement, a shift rail projectingaxially through said cap members and slidably supported at its oppositeends in the central bosses of said pistons, a shift fork mounted on saidshift rail between said cap members, a coil spring extending axially ofeach of said pistons between the closed ends of the latter and said capmembers for biasing said pistons to a position in which the closed endsof said pistons are disposed against said end walls of said cylinders,and for biasing said cap members in a direction outwardly of the openends of said pistons into engagement with opposite end faces of saidshift fork to position the latter in a neutral position intermediatesaid cylinders, and openings in said end walls of said cylinders foradmitting fluid under pressure into the outer ends of either cylinder tomove the piston therein toward the other of the pistons against theforce of said spring means in each piston and thereby move said shiftfork and said shift rail out of neutral position.

FRANCIS MARION HOGUE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

